1. Field of the Invention
The present invention relates to motor control centers and, more particularly, to a method for removing an auxiliary contact from a motor controller unit housed in a motor control center, and an associated apparatus.
2. Description of Related Art
A motor control center (MCC) is a modular cabinet system for powering and controlling motors, and may typically be found in a manufacturing or factory setting. The MCC is an assembly of one or more enclosed sections having a common power bus and principally containing motor control units. Such motor control units are housed in so-called “buckets” received within the MCC cabinet. The motor control units may include one or more motor starters, which are electrically-operated switches using magnetic induction to provide the startup current for a motor. Each motor starter includes one or more auxiliary contact devices (so-called “blocks”), which function to provide memory to control circuits, to show operational status of equipment, to show faults with the equipment, and/or to complete the circuit for another pierce of equipment.
Unfortunately, the auxiliary contact devices can fail and, in those instances, must be replaced. A typical MCC may have 20-30 buckets and, thus, each MCC includes a relatively large quantity of auxiliary contact devices which at some point will need replacing. To replace an auxiliary contact device, the bucket containing the auxiliary contact device must be removed from the MCC cabinet because the walls of the bucket generally prevent the auxiliary contact device from being accessed and removed while the bucket is still positioned within the MCC cabinet. Removing a single bucket from the MCC, however, terminates the overall circuit and shuts down the MCC.
As such, it would be desirable to provide a method and associated apparatus capable of removing an auxiliary contact device from a motor starter without removing the bucket from the MCC cabinet, so as to reduce instances of downtime of the MCC for replacing such auxiliary contact devices and, for instance, to reduce the risk of electrical shock to an operator performing such a replacement.